This invention relates to a method for manufacturing reinforced oriented strand boards, particularly to one including steps of forcefully filling a kind of resin in an oriented strand board, fully filling gaps in the board to manufacture oriented strand boards having firm structural strength and fire-resistant characteristic.
The higher the living standard of people becomes, the more the demand of wooden material grows, but unfortunately natural forests grow very slowly. Although fast growing trees newly planted provide the lacking quantity of wooden material, trees planted are almost softwood having limited use, and they are impossible to substitute the hardwood used more widely than soft one. Therefore, human beings have been making efforts to develop artificial fabricated wood boards, such as veneers, fiber boards, strand boards, etc. so as to replace various natural wood boards. The important factors of artificial wood boards are hardness, durability, and stability, which can reach nearly the same as natural hard wood. Then additives may be added in adhesive or glue to make veneers, fiberboards for special purpose and use so as to improve their property, such as moisture-resistance, fire-resistance, erosion-resistance, and insect-resistance.
One of the artificial wood boards most similar to natural hard wood may be oriented strand boards called shortly as OSB (Layer-to-layer cross oriented strand pattern board). It is made of many layers of small wood veneers of the same direction fiber crossly overlapped. Its fiber layers are composed of many small wood veneers having its length (along fiber direction) several times than its width and arranged parallel to one side of the veneers. This OSB, made of many layers of the same direction fiber alternately vertically overlapped board is disclosed at length in an early U.S. Pat. No. 3,164,511 (1965) regarding to its manufacturing processes and property. The advantage of OSB is the property almost similar to natural wood, and adjustable in its size, may have the length as long as 40 feet, and its thickness also possible to be made to order. Furthermore, OSB makes use of material waste produced in wood factories, especially contributive to the environment.
The property and appearance of present OSB have been improved in U.S. patents such as U.S. Pat. No. 4,364,984 (1981), U.S. Pat. No. 5525394 (1995), U.S. Pat. No. 5,736,218 (1998), etc. It has been improved in manufacturing processes, changing the shape of fiber pieces, arrangement, structure and adhesives, and increasing its good appearance, physical property and weather-endurance. But OSB having fire-resistant property has not been developed much, and only U.S. Pat. No. 5,443,894 (1994) offers a fire-resistant OSB having adhesive added with expandable graphite, but there are not any other reports and news about fire-resistant OSB.
Although fire-resistant OSB can be made by means of a traditional vacuum pressure filling method (for example, CNS 300/0101), injecting various fire-resistant chemicals (such as CNS4180/K1195, CNS4181/K1196, CNS4182/K1197, and CNS4183/K1198) in OSB to obtain fire-resistant effect. However, OSB has a loose structure itself so when a water-soluble fire-resistant chemical is injected in it, inflation caused by water forms a great damage to the physical property of OSB, reducing its availability.
The objective of the invention is to offer a method for manufacturing reinforced oriented strand boards, wherein finished oriented strand boards are made by injecting melamine-formaldehyde resin or phenol-formaldehyde or mixtures of melamine-urea-formaldehyde resins in them by means of a vacuum pressure impregnation processes, and then heated and pressed to harden the resin. As the oriented strand boards have gaps impossible to completely fill up, still many of them remained therein. Therefore, the resin injected therein may fill up the gaps remained therein to infiltrate and wrap the strand board not only to make it fire-resistant, but to improve its whole strength conspicuously.